Chemical Industry and Engineering Progress ›› 2018, Vol. 37 ›› Issue (12): 4932-4938.DOI: 10.16085/j.issn.1000-6613.2018-0528

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Molecular dynamic simulation of oil pollutants desorption from rough quartz sand surface by CTAB extraction

ZHANG Yan1,2, ZHU Xinzhe1,2, MENG Qi1,2, TIAN Linqing1,2, WU Guozhong1,2   

  1. 1 School of Environment, Tsinghua University, Beijing 100084, China;
    2 Division of Ocean Science and Technology, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, Guangdong, China
  • Received:2018-03-19 Revised:2018-08-22 Online:2018-12-05 Published:2018-12-05

分子模拟十六烷基三甲基溴化铵对石油污染物在粗糙石英砂表面脱附的影响

张岩1,2, 祝新哲1,2, 孟琪1,2, 田林青1,2, 吴国钟1,2   

  1. 1 清华大学环境学院, 北京 100084;
    2 清华大学深圳研究生院海洋科学与技术学部, 广东 深圳 518055
  • 通讯作者: 吴国钟,讲师,研究方向为土壤石油污染评估与修复技术及气体水合物应用。
  • 作者简介:张岩(1992-),男,硕士研究生,研究方向为土壤石油污染修复。
  • 基金资助:
    深圳市科技研发基金(JCYJ2016051303756736)及深圳市海外高层次人才创新创业专项资金(KQJSCX20170330151956264)项目。

Abstract: Solvent extraction is widely used in the restoration of oil contaminated soil, and the changes of soil microstructure before and after extraction will further affect the migration and transfer of oil pollutants in soil. Using molecular dynamics simulation method, this paper researched oil pollutants (n-dodecane) detachment in hexadecyl trimethyl ammonium bromide (CTAB) aqueous solution from quartz sand surface. Grooves with different widths or depths were constructed on quartz sand surface, which represented the mineral surface coarse structure. The results showed that:① the main driving factors of the desorption process of the n-dodecane molecules in grooves are the CTAB molecules and the n-dodecane polymer outside grooves; ② Reduction of the width of grooves or increase of the depth of grooves inhibit the desorption of n-dodecane molecules, and also restrain CTAB molecules from promoting the removal of oil; ③ The concentration of CTAB is not proportional to the percentage of desorpted n-dodecane molecules. The system containing 16 CTAB molecules may achieve a better degree of n-dodecane molecules detachment than the systems containing 0 or 32 CTAB molecules.

Key words: molecular simulation, oil pollutants, quartz sand, surface roughness, CTAB, solvent extraction

摘要: 溶剂萃取法广泛应用于石油污染土壤的修复,萃取前后土壤微观结构的改变会影响石油污染物在土壤中的迁移和传递。本文利用分子动力学模拟方法,通过在石英砂表面上构造不同的凹槽代表矿物表面粗糙的结构,研究十六烷基三甲基溴化铵(CTAB)水溶液萃取石油污染物(正十二烷)的过程。结果表明:①脱附过程的主要驱动力为凹槽外的正十二烷和CTAB分子与凹槽内正十二烷分子之间的相互作用;②凹槽的宽度减小或者凹槽的深度增加,均会增加槽内正十二烷分子的脱附难度,同时还会影响CTAB分子的促进脱附效果;③CTAB分子对石油脱附的促进效果随其浓度的增加而减弱,当持续增加体系中CTAB的含量时(不同模拟体系中的CTAB分子数量分别为0、16、32),会抑制其促进脱附的效果。

关键词: 分子模拟, 石油污染物, 石英砂, 粗糙表面, 十六烷基三甲基溴化铵, 溶剂萃取

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